1. Field of the Prior Art
The present invention relates to an IC tester system, and more particularly, to a DUT board for eliminating electrostatic discharge (ESD) damage.
2. Description of the Prior Art
The reliability of products is a very important factor in the manufacturing process of IC chips. The reliability can be simply defined as the lifetime of a product under normal conditions. The IC chip manufacturers need to know the lifetime of products in advance; therefore an accelerated lifetime test is used to forecast the average lifetime. The theorem of the accelerated lifetime test is to test the lifetime of products under strict conditions, such as in a high temperature or pressure environment, and to high voltage or high current. Then the lifetime model is used to forecast real lifetime under normal conditions. Typical reliability tests are classified into wafer-level reliability (WLR) tests and package-level reliability (PLR) tests. The WLR test means to test the wafer directly in a production line. The PLR test means to segment and package a wafer as devices-under-test (DUT), and to insert those DUT into a DUT board to test in a high temperature oven. The stress condition of the PLR test is closer to the normal working conditions, and therefore the test result is widely accepted.
Please refer to FIG. 1. FIG. 1 is a schematic diagram of an IC tester device according to the prior art. As shown in FIG. 1, the IC tester device 10 of the prior art comprises a temperature control oven body 12 and an oven door 14. The oven door 14 has a thermal-insulated material 16 thereon, such as rubber. The thermal-insulated material 16 is pasted in the oven door 14 for maintaining proper testing temperature, and has long gaps so as to allow a DUT board 30 to pass through and fix on the oven door 14. The DUT board 30 includes a DUT socket 34 for installing a DUT, a testing conducting wire 36, and a testing interface (also called bonding fingers) 38 for connecting to a port of a testing unit (not shown). When the test is performed, the following steps are executed: installing the packaged DUT 32 to the DUT socket 34, loading the DUT board 30 into the gap of the thermal-insulated material 18 in the oven door 14, closing the oven door 14, and performing the electric property test in a high temperature environment provided by the temperature control oven 12.
However, the IC tester device 10 of the prior art is not able to prevent the ESD damage. When the DUT board 30 is loaded to the gap of the thermal-insulated material 18 in the door 14, the ESD generated by the friction between the testing interface 38 and the thermal-insulated material 16 will damage the DUT. Similarly, after the test completes, when the DUT board 30 is unloaded, the ESD will also damage the DUT.
The present remedy for the ESD problem is to use specific fixtures. The IC DUTs are isolated one by one with the specific fixtures by hand when installing to the DUT socket of the DUT board. After loading the DUT boards to the oven door, the specific fixtures of each DUT are taken off one by one by hand for performing the IC test.
Similarly, when the IC test completes, the same procedure are performed to prevent the ESD damage. Although the specific fixtures can avoid ESD, it costs too much time to put on and take off the specific fixtures. Furthermore, with the complicated steps, the DUT may be damaged because of human negligence. Thus the purpose of decreasing the cost and improving the effects of the IC test is still not achieved. As a result, an IC tester for preventing damage from ESD with simple related operation method is eagerly necessary.
It is therefore a primary objective of the claimed invention to provide an IC tester system for eliminating the electrostatic discharge (ESD) damage to solve the problem caused by ESD during the testing process of the prior art.
According to the claimed invention, an IC tester system for eliminating the ESD damage is disclosed. The IC tester system comprises a temperature control oven and at least a DUT board. The temperature control oven includes an oven body and a door having a thermal-insulated material thereon. The DUT board includes a board body, at least a DUT socket, a testing interface, a grounding interface, a testing conducting wire, and a dummy conducting wire. The ESD generated by the friction between the testing wire and the thermal-insulated material during the loading and unloading action of the DUT board is grounded out via the dummy conducting wire and the grounding interface.
The IC tester system of the present invention has a dummy conducting wire and a grounding interface so that the ESD generated by the friction between the testing wire and the thermal-insulated material can be grounded out in advance before testing. This can prevent the DUT from being damaged by the ESD, and can further improve the accuracy of the IC electric property test.